Changes

===Introduction===

===Introduction===

Cyathostomins are a group of '''small strongyles'''. The majority of cyathostomins are similar in terms of both morphology and behaviour.  There are over 50 different species of small equine strongyle, and they are of huge significance throughout the United Kingdom.  They commonly cause severe acute diarrhoea and colic.

Cyathostomins are a group of '''small strongyles'''. The majority of cyathostomins are similar in terms of both morphology and behaviour.  There are over 50 different species of small equine strongyle, and they are of huge significance throughout the United Kingdom.  They commonly cause severe acute diarrhoea and colic.

*Buccal capsule shape

They are small worms, generally less than 1.5cm long.  They also have a distinctive, small buccal capsule.  They also have two rows of leaf crowns, both internal and external.

*Double row of leaf crowns

 

==== Life-cycle ====

==== Life-cycle ====

L1-L3 occurs within the envelope. The L3 then exits the sheath in the small intestine, and then concentrates within the '''Lieberkuhn's gland'''. At this stage they are known as EL3, and have two potential options.  Firstly, they may either become hypobiotic, remaining dormant for several months to years.  This usually occurs Autumn-Winter.

L1-L3 occurs within the envelope. The L3 then exits the sheath in the small intestine, and then concentrates within the '''Lieberkuhn's gland'''. At this stage they are known as EL3, and have two potential options.  Firstly, they may either become hypobiotic, remaining dormant for several months to years.  This usually occurs Autumn-Winter.

Or they may evolve directly and emerge 8-10 weeks later as LL3. They will then evolve into L4, at which stage they will emerge from a nodule.

Or they may evolve directly and emerge 8-10 weeks later as LL3. They will then evolve into L4, at which stage they will emerge from a nodule.

*Infection by ingestion of L3

 

*Larvae invade mucosa of large intestine

Encysted, or hypobiotic larvae are unaffected by [[Anthelmintics Drugs]]. These encysted larvae represent around 50% of the total population.  After emergence of the cyst, L4 transforms into L5. They then transform into adults in the lumen.

*Larvae may develop to L4 without interruption

 

If hypobiosis does not occur, the prepatent period is 6-14 weeks.

*L4 emerge into gut lumen and mature to adult worms

 

*Prepatent period 8-12 weeks (depending on species)

==== Pathogenicity ====

==== Pathogenicity ====